1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to data processing systems having the ability to generate trace data output.
2. Description of the Prior Art
It is known in the field of data processing systems to provide mechanisms for generating trace output data. This trace data may be used for diagnostic and debug purposes during the development of hardware and/or software. A problem that arises within such data processing systems is that the volume of trace data can be so large that there are insufficient resources to buffer the trace data on the device when captured and before output and/or insufficient bandwidth to send the trace data out of the device. One way of dealing with this is to discard trace data which it is not possible to buffer or transmit out of the device. However, this suffers from the disadvantage that critical diagnostic information may be present within the discarded trace data. Another possibility is to stall the device until space becomes available within the trace data buffer or capacity becomes available to transmit the trace data off the device. A disadvantage of this approach is that stalling the device, or otherwise changing its timing, may influence the operation of the device in a manner which masks or alters a fault being investigated or introduces additional faults.